Picked up some gear whine first passes on the track, any way to backbrace a 12 bolt?
03-29-2010, 04:11 AM
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Picked up some gear whine first passes on the track, any way to backbrace a 12 bolt? I have a Moser 12 bolt in my 408ci/TH350 car with an eaton posi with 4.10s. It was purchased built from a sponsor here and has been in the car for roughly 5k street miles with 0 track passes. A few weeks ago I finally got it on the track and made roughly 10 passes with a 325/50/15 mickey radial.
Several of the passes were on the foot brake, and only 3 were on the trans brake. 2 of them the car spun/hopped about 10 feet out, and 1 the car dead hooked. I'm going to assume the spinning was due to not having a drag rear swaybar because the left side of the car was lifting a lot and I know the wheel hop was probably a big contributing factor, but on the 1 pass where it dead hooked and the front tires came up I noticed a LOUD whine afterwords. I had just changed the fluid about 200 miles before the track passes and the gears and wear pattern looked great. The car managed a 1.49 60ft.
The whine is only there when you're maintaining/slightly accelerating or when decelerating from around 10mph - 0mph. Harder accel it's not there and on the brakes it's not there untill you're roughly at 10-15mph all the way until a complete stop.
Instead of speculating on the cause (bad bearing, stretched pinion, etc) and tearing in to this more than once, I'm just going to replace all of the bearings and put in a new ring and pinion. I've been wanting to change gear ratio anyways so now is the best time. My question is.. is there anything that can be done to prevent this? I know a trans brake is hard on the rear, but the car is less than 500rwhp through an auto and I dont think it should be killing a rear on the first day at the track.
I will be installing a BMR drag bar and a cage so that should stiffen up my chassis and crooked launch issue. I want to rebuild it and forget about it basically. A friend of mine was telling me he'd heard/seen some sort of backbrace on a 12 bolt in a drag camaro. The camaro has since been sold to someone out of town so there is no chance of me seeing it, but apparently it has fixed all rear issues the owner was having. Instead of killing gears every weekend he had one set for over a year. If I can't do that with this rear i'll sell it and buy a 9." Anyone seen a setup like that? Thoughts on it? I'll be pulling the rear to set it up on the bench so this time would be ideal for any kind of welding that needs done.
I do plan on spraying the car down the line so already having rear issues with my $2500 rear (abs, tcs, etc) is pretty upsetting.
Several of the passes were on the foot brake, and only 3 were on the trans brake. 2 of them the car spun/hopped about 10 feet out, and 1 the car dead hooked. I'm going to assume the spinning was due to not having a drag rear swaybar because the left side of the car was lifting a lot and I know the wheel hop was probably a big contributing factor, but on the 1 pass where it dead hooked and the front tires came up I noticed a LOUD whine afterwords. I had just changed the fluid about 200 miles before the track passes and the gears and wear pattern looked great. The car managed a 1.49 60ft.
The whine is only there when you're maintaining/slightly accelerating or when decelerating from around 10mph - 0mph. Harder accel it's not there and on the brakes it's not there untill you're roughly at 10-15mph all the way until a complete stop.
Instead of speculating on the cause (bad bearing, stretched pinion, etc) and tearing in to this more than once, I'm just going to replace all of the bearings and put in a new ring and pinion. I've been wanting to change gear ratio anyways so now is the best time. My question is.. is there anything that can be done to prevent this? I know a trans brake is hard on the rear, but the car is less than 500rwhp through an auto and I dont think it should be killing a rear on the first day at the track.
I will be installing a BMR drag bar and a cage so that should stiffen up my chassis and crooked launch issue. I want to rebuild it and forget about it basically. A friend of mine was telling me he'd heard/seen some sort of backbrace on a 12 bolt in a drag camaro. The camaro has since been sold to someone out of town so there is no chance of me seeing it, but apparently it has fixed all rear issues the owner was having. Instead of killing gears every weekend he had one set for over a year. If I can't do that with this rear i'll sell it and buy a 9." Anyone seen a setup like that? Thoughts on it? I'll be pulling the rear to set it up on the bench so this time would be ideal for any kind of welding that needs done.
I do plan on spraying the car down the line so already having rear issues with my $2500 rear (abs, tcs, etc) is pretty upsetting.
